Air filtering apparatus



- March 7, 1950 E. c. GWALTNEY ETAL 2,500,123

AIR FILTERING APPARATUS Filed April 27, 1945 6 Sheets-Sheet l March 7,,1950 v c. GWALTNEY ETAL 2,500,123

AIR FILTERING APPARATUS 6 Sheets-Sheet 2 Filed April 27, 1945 AIRFILTERING APPARATUS 6 Sheets-Sheet 3 Filed April 27, 1945 March 7, 1950E. c. GWALTNEY ETAL.

AIR FILTERING APPARATUS 6 Sheets-Sheet 5 Filed April 27, 1945 March 1950E. c. GWALTNEY ETAL 2,500,123

AIR FILTERING APPARATUS G Sheets-Sheet 6 Filed April 2'7, 1945 PatentedMar. 7, 1950 AIR FILTERING APPARATUS Eugene C. Gwaltney, Biddeford, andWilliam Shaw and Eliot B. MacLean, Saco, Maine, assignors to Saco-LowellShops, Boston, Mass, a

corporation of Maine Application April 27, 1945, Serial No. 590,592

8 Claims. 1

This invention relates to air filters, and is more especially concernedwith the requirements of apparatus of this type intended for use intextile mills.

In all of the earlier operations in connection with the preparation ofcotton fibers for spinning, including bale breaking, opening, pickingand cleaning, the cotton is conveyed in a current of air. Theseoperations involve the separation of the fiber from the dirt, leaf,sand, and other foreign materials, most of which is carried along by theair stream and remains in the latter even after the cotton has beenseparated from the air stream, either in the machines themselves or inthe condensers. In order to provide suitable working conditions in anyroom where such operations are performed, it is necessary to filter theair used in connection with them before it can be returned to the room.

The type of filter which has proved most practical for this purpose isthat shown in Patents Nos. 2,057,369, 2,206,297, and 2,315,278. In allof them the filtering medium or mat is composed mainly, and usuallyentirely, of fibers filtered out of the air stream itself. While thesefilters represent a highly important and practical solution for the airfiltering problem as it exists in such places as picking and openingrooms, nevertheless it is recognized that they do not take out all ofthe fine dirt, and an unfortunate fact is that the line silica dust isnot completely removed by any of the filters employed in textile mills.This material when inhaled into the lungs of the workers is highlyirritating and, so far as we now know, the human body has no way ofgetting rid of it.

Practical considerations complicating this filtering problem are thefacts that th filtering operation must be continuous and that the volumeof air the filters must handle is very large, a single picker fan, forexample, discharging approximately 1000 to 1200 cubic feet of air perminute when in operation.

The present invention is especially concerned with the problemspresented by the foregoing considerations, and it aims to devise athoroughiy practical solution for those problems.

The manner in which it is proposed to accomplish this object will bereadily understood from the following description when read inconnection with the accompanying drawings, and the novel features willbe particularly pointed out in the-appended claims.

3 In the drawings:

Fig. 1 is a plan view of an opening and picking machine organizationincluding filtering apparatus embodying this invention and illustratinga typical use for apparatus of this type;

Fig. 2 is a plan view, partly in horizontal section, of a filteringstructure embodying this invention;

Fig. 3 is a vertical, sectional View taken approximately on the line3-3, Fig. 2;

Fig. 4 is a vertical, sectional view taken approximately on the line 4-of Fig. 8;

Fig. 5 is an end view of a secondary filter unit embodying features ofthis invention;

Fig. 6 is a vertical, sectional view through one of the outlets of thesecondary filtering unit illustrating the means for releasablysupporting a filtering bag;

Fig. 7 is a front elevation of a portion of the secondary unit shown inFig. 5; Fig. '7, however, being on a larger scale;

Fig. 8 is a vertical, sectional view through the main filter unit;

Fig. 9 is a side elevation, with some parts broken away, of the mainfilter unit;

Fig. 10 is a vertical, sectional view showing details of the main filterdrum and parts associated therewith;

Fig. 11 is a sectional view taken at the edge of the filter drum,showing the air seal used at the ends of the drum;

Fig. 12 is a front elevation of certain elements of the drive for thefilter drum; and

Fig. 13 is a side view of the parts of the driving mechanism shown inFig. 12.

Referring first to Fig. 1, a typical opening and picking system is thereshown in which filtering apparatus embodying this invention isincorporated. It comprises a series of bale breakers B delivering cottonto a single feed table T from which it is carried into a vertical openerV, and is then transferred through the pipe 2 to a condenser C of acommon commercial form. The blower with which this condenser is equippedcreates the suction which picks up the cotton from the delivery end ofthe feed table, carries it into the opener V, and then through the pipe2 to the condenser C for the lattice opener L0. The air discharged fromthe blower of this condenser is led directly back under the pipe 2 intoa primary filter unit 1. This air contains considerable fiber and muchdirt, and the air which flows through the filter and is dischargedtherefrom is led through pipe connections 6 to a secondary filter unit fof a different form, and which is adapted to take out practically all of3 the fine dirt carried by the air stream which enters it.

In this particular system, also, the cotton acted upon by the latticeopener is carried through the suction pipe 8 to a condenser C whichdrops it into the feed hopper of a single process picker system Plocateddirectly under the pipe 8. The condenser, as usual; includes a'blower creating the suction which produces the air current through thepipe 8, and the exhaust.

air from the condenser is led back through a pipe III to a filter F,with which is associated a secondary filter F, these two units beinglike those shown at J and 1" respectively. The fil-- tered airdischarged from the secondary units F and f flows directly into thepicker room, but the filters have extracted both the fiber and the dirtfrom it so thoroughly that'it is entirely suitable for reuse.

The primary unit F with the secondary unit F associated with it in. a.unitary structure is illustrated in Figs. 2 and 3. The former is acontinuous filter of the rotary self-cleaning type, similar to thoseshown in the last two patents above mentioned, but itinvolvesnovelfeatures of construction. It comprises a rotary filteringdrum I2 enclosed in a casing I 3, the details being shown more clearlyin Figs. 8 and 9, as willlater be described. The air to be filtered isled into the casing through an intake I 4 where it fiows around thegreater part .of the circumference of the cylindrical drum I2, throughthe peripheral surface of said drum into the interior of it, and thenout through the open ends of this member. The surface of the drum is ofa. foraminousnature which screens out the fiber very thorou hly. As thisoperation continues, the fiber collects on the surface of thescreen,.coooerating with it to form a mat which, when established, isanef-f fective filtering medium. As the mat builds up and the drum isslowly revolved. it comes within the range of operation of two stripperrolls .I 5'-I 5" which revolve in opposite directions and remove-Successive the mat gradually from the cylinder. portions of the drumleaving the stripper rolls are brought into the range of operation of acleaning brush I6 which serves to take off the dirt or fiber adhering tothe screen.

In this region adjacent to the brush, the screen is protectedfromsuction by the fact that the entire space through which it passes issubstantially isolated, partly by the roll I5 and the usual sealingflaps, and partly, also, :by the portion of the casing cooperating withthese elements to enclose this area. Two clean-out doors are provided atthe bottom of the'chamber'in which the drum I2 revolves, one indicatedatw and hinged at its upper edge, but normally closed by the pivoted latch.r, while the other is hinged at its right hand edge to swing downwardlyand is closed by the latch 1 The details of construction of the filterdrum are better illustratedin Figs. 9 and 10. As shown in the latterfigure, the drumcomprisestwoend' from it, the." latter: being integral.with airing .4 section 22 which is bolted to one of the partitions I3,Fig. 8, of the main casing I3.

The operating mechanism for the drum comprises a cam 25, Fig. 9, mountedon a shaft 26 which is driven from a motor 23, Fig. 2, supported on ashelf 24 at one side of the air intake pipe I 4. This cam runs incontact with a cam follower roll carried by an arm 2! fast on'a'rockshaft 28 which is supported in bearings at the front or intake side ofthe casing I3. A second arm 29 fast on this shaft carries a weight whichoperates to hold the roll on the arm 27 continuously against theperiphery of the cam. Another arm 39 also secured on said rock shaft isprovided with a series of holes spaced therealong, in any one of whichthe pivot pin for a link 3I may be secured. Its opposite end is pivotedto an arm 32 loose on the shaft 33. The pivot pin secured to the armjust mentioned carries a dog or pawl 34, Figs. 8 and 9, which rests bygravity on the toothed edge of a ratchet wheel 35 rigidly secured tosaid shaft 33. Consequently, as the cam is revolved, the motion soimparted to the arm and pawl 34 gives'the ratchet wheel 35 and the shaft33 an intermittent rotative movement; The design of the cam is such thatthe wheel 35 is revolved slowly most of the time. A holding pawl S, Fig.9, also engages the ratchet-wheel and prevents reverse movement of it.

Sprocket and chain connections 31, Figs. 8 and 9, between the shaft 33and the shaft of the clearer roll :5 drive the latter, and additionalgear connections between the two clearer rolls I5'and I5 at the oppositeside of the machine drive the latter roll. Also, on the shaft of theclearer roll I5 is a pinion 40, Fig. 8, meshing with and driving a gearM on the end of the shaft I8 of the filter drum. It should also beobserved that the shaft'33 supports the brush I6. Consequently, all thedriven parts of the filter structure derive their power from the cam 25and motor 23.

In this connection it maybe pointed out that,

because the two clearer rolls I5 and I 5 must have some relativeseparating movement to accommodate variations in thickness of the webwhich they remove from the filter drum, the shaft of the second roll I5is mounted in slidable bearings which are pressed yieldingly toward thecompanion roll I5 by springs, one of which is shown in Fig. 13 at 61.Also, for this same reason. the two roll shafts are not geared directlyto each other but are connected through intermediate gears which permitthe yielding movement of this roll I5 toward and from its cooperatingroll I5.

. As best shown in Figs. 12 and 13, the shaft l5 carries a pinion I5a,meshing with another pinion I5b directly above it, and the latter meshesconstantly with and drives a third pinion I which also is in constantmesh with a fourth pinion I503 fast on the roll shaft I5. Thus the drivefrom the roll I5 to its companion shaft is continuous and positive, butstill permits the necessary yielding action between the two rolls toaccommodate the feeding of a web varying substantially in thickness.

A novel means for'sealing the ends of the-drum I2 against the-escape ofdust-laden air through the joint between the partition or casing membersI3 and the peripheral surface of the end rings I'I, isbest shown in Fig.11. Each ring'is recessed circumferentially atits outer edge, as shownat I T, to receive a circular seal'IEl. This member comprisesa core madeof wire; leather, or any other suitable material, around which'iswrapped a covering of some fibrous sheet materiaL-such. as

felt or leather. The margins are folded back together, face to face, andare secured in a recessed portion of the annular frame piece 22 byscrews or rivets l9. These frame members 22 are bolted in position afterthe drum has been properly placed in the casing, and, in connection withthis operation, the seal automatically is properly positioned in thegroove ll" provided for it, where it makes a very effective closure forthe joint between the drum and the stationary cam ring 22 whichreleasably holds the sealing ring l9 against the end ring I! of thedrum.

The space in the casing is divided by partitions into the filteringchamber G, Figs. 3 and 4, in which the drum revolves, and end chambersI-II-I, Fig, 2, into Which the air flows from the open ends of the drum22. From these chambers the air enters another chamber or passage I,immediately above the filtering chamber, and then is discharged throughan opening J. When both the primary and secondary sections of the filterare built into an integral unit, as in Figs. 2 and 3, the opening Jadmits the air directly into the casing of the secondary unit F. Thisunit comprises a distributor or header 44, Figs. 2 and 3, having achamber K into which the air flows freely from the outlet J of thecasing 13. Except for this outlet the casing 44 is completely closed onits top, ends, and sides, but its bottom or floor is provided withseveral outlets (in this instance four), each eouipped with a fixture orfitting 45 adapted for the attachment thereto of a bag 46. The lattermay conveniently be made of a tightly woven fabric, napped on its innersurface. The bag is of generally cylindrical form with a closed bottom,and it is fastened at its top to a ring 41, Fig. 6. which is providedwith a flared neck around which the mouth of the bag can be convenientlytied or secured by a spring, or in any other convenient manner. Thefitting or fixture 65 also includes a metal ring of angular section andan internal plain ring it fastened to it by screws. a thick layer offelt being secured between these two parts. Its u per edge acts as aseal for the cover 48 of the outlet and its lower edge engages the uppersurface of the bag ring 41' and seals the space between it and thefixture 45.

In order to secure the bag to the fixture 45 for quick attachmentthereto or removal therefrom, each of the rings 4'! is provided with arearwardly extending fork 50, Fig. 6, notched at its lower side toreceive a pin which is supported in an extending arm, which is shown at52 in Fig. 6. Th s arm is made integral with the fixture 45 and the forkprojects into both sides of the arm. At the opposite side of the fixtureit is provided with a latch 53, pivoted at 5 1, to swing into the spacebetween the fingers of a forked extension 55. which is exactly like thatshown at 50, and is also made integral with the ring 41. The lower endsof these fingers are notched to receive a pin 56 on the latch 53.

When the parts are in the relationship shown in Fig. 6. they look thering 41 and the bag secured to it, in their operative relationship tothe fixture 45. However, by swinging the latch 53 in a clockwisedirection, the left-hand end of the ring may be released, and then bypulling the ring slightly toward the left it may be completelydisconnected from the fixture and the contents of its bag may be emptiedinto any convenient receptacle. Thereafter it may be returned to itsoperative position by a reversal of the operations just described.

the filter elements themselves in this secondary As above stated, thefiltering operation must be continuous, and for this purpose the primaryunit is made of the self-cleaning type. The secondary unit, however,includes filtering bags which must be emptied at intervals. For thispurpose, and in order not to interrupt the filtering operation, severalof these bags are used, and provision is made for cutting any one ofthem out of the air stream without interrupting its flow to the others.It is for this purpose that the covers 48 are provided for therespective outlets.

As shown in Fig. 6, the cover 48 is loosely secured by a bolt 58 to oneend of an arm 60, the opposite end of which is rigidly secured to therock shaft 6! which extends horizontally across the casing 44 just aboveits floor. It projects through the front of the casing, its forward endbeing reduced in diameter at that point. Outside the casing a handle 62is secured rigidly to it, as shown in Fig. 6. The handle includes aplunger having a knob 63 at its outer end, with a spring (not shown)urging it inwardly, so that it can enter either one of two holes formedin the segmental guide plate 64, Fig. '7, which is secured to the frontface of the casing 44. When the handle is down the cover also is in itsdown or closed position, as shown in Fig. 6, but when the handle isswung up and its plunger is entered in the hole 65, Fig. '7, the coveris then looked in its open position. By loosely mounting the cover plate48 on the arm 60, it is free to seat itself tightly upon the upper edgeof the felt ring clamped between the parts 45 and 45'.

A typical application of this invention is illustrated in Fig. 1. As soused, the air stre m carrying lint and dust flows initially into theprimary fi ter wh ch will take out in the neighborhood of of the solidmaterial and. under some circumstances, may remove even a higherpercentage. From this filtering unit the air stream with the very fineresidual dust entrained in it. goes into the secondary or bag filterunit which removes practically all of th s foreign material. Almost nofiber passes through the first filter. and this is important because anygreat amount of material of this nature would load up the bags toorapidly. At stated intervals the bags are removed. one at a time, andemptied. This operation takes only a moment for any indivi dual bag. Ifit is desired to make such removal while the pickers or other units withwhich the filtering apparatus is associated continue in operation, thatcan readily be done simply by closing off the air stream from the bag tobe removed, emptying it, replacing it, and then opening the cover againfor that particular bag. And these operations can be repeated with theother three bags.

While the preferrd filter is that in which both the primary andsecondary units are combined in a single structure, as shown for examplein Figs. 2 and 3, it is often necessary, or desirable, in some mills, toinstal a filter unit where there is not room for this combinedstructure. Under such circumstances the arrangement shown in Fig. 1 maybe used where the main filter unit f is placed in the position mostefiicient for its operation, and the supplemental unit f is connectedwith it through a pipe, such as that shown at B. In such an arrangementthe pipe just mentioned opens into a small casing which is connectedwith, and secured to, the header 44, just as is the casing at IS in theconstruction shown in Figs. 2 and 3. It will also be evident that whilei uriit'are bags,'these may beireplacedby cylinders or otherelementsequivalent to the bags.

It should be observed that this combination of a continuously operatingfilter. in which the filter mat is built up of fiber taken out of theair stream itself, and a supplemental or secondary unit into which onlythe fine dirt is delivered, maximum use is made of those functions ofthe two types of filters which each is admirably adapted to perform. Thecombination of them eliminates the faults and deficiencies of both,while combining their virtues. The end result is to filter the airso'thoroughly that it is entirely suitable for return to the opening,picking or other room from which it was originally taken.

iile we have herein shown and described a preferred embodiment'of ourinvention, it will be evident that the invention may be embodied insomewhat different forms without departing from the spirit or scopethereof.

Having thus described our invention, what we desire to claim as new is:

1. An air filtering apparatus corn rising a rotary open-ended filteringdrum, a casing in which said drum is mounted, said casing beingconstructed to conduct the air to be filtered into contact with theperipheral surface of said drum but to confine said contactsubstantially to sei surface, said drum having end members supportingthe peripheral surface of the drum, and said members each having acentral hub, an outer ring and arms connecting the hub with the ring, ashaft extending through and secured to said hubs, and spiders secured toportions of s'aid'casing and positioned outside the ends of said drum,said spiders having hub portions supporting bearings in which said shaftis mounted.

2. An air filtering apparatus comprising a 1'0- tary open-endedfiltering drum, a casing in which said drum is mounted, said casingbeing constructed to conduct the air to be filtered into contact withthe peripheral surface of said drum but to confine said contactsubstantially to said surface whereby lint filtered out of the airstream by said drum will build up on the peripheral surface thereof andform a filter mat, a pair of stripper rolls extending parallel to theperipheral surface of saiddrum at one side thereof, camdriven mechanismfor revolving said rolls to cause them to remove said mat gradually fromsaid drum, means supporting one of said rolls for yielding movementtoward and from the other, said driving means for the rolls includinggearing positively connecting them and arranged to drive themapproximately continuously notwithstanding the relative movement of saidstripper rolls to accommodate wide variations in the thickness of thematerial removed from the drum by them.

3. An air filtering apparatus comprising a rotary, open-ended filteringdrum, mechanism for revolving said drum, a casing in which said drum ismounted, said drum having end rings grooved circumferentially in theirouter end surfaces, and air sealing rings secured to said casing andeach comprising a core with a strip of sealing material folded aroundit, the edges of said strip being fastened to said casing and lateralsurfaces of said material where it is wrapped around the core lyingsnugly in said grooves in the end rings of the drum.

' 4. An air filtering apparatus comprising a rotary open-endedfiiteringdrum, mechanism for revolvingsaiddrum; a casing having afiltering chamber in: which; said: drum; is. mounted; the

casing being constructed to conductair to-be filtered into contact withthe'peripheral surface of said drum but to confine said contactsubstantially to said surface, the casing. also including end chambersinto which the: air flows from the respectiveopen ends of said drum,said casing including afourth chamber into which said end chambersconduct the air, a secondary bag-type filter unit comprising a headerhaving a plurality of outlets located side by side, means for conductingthe air from said fourth chamber into said header, said header outletsbeing formed in fixtures mounted in the wall of. said header andconstructed for the releasable attachment thereto of individualfiltering bags, hinged covers associated with the respective fixturesfor closing and opening said outlets, and handles, outside of saidheader, connected with said respective covers and operable to move theminto their open or closed positions selectively, whereby the air streammay be shut off from any individual bag, when desired, to remove orreplace it.

5. An air filtering apparatus comprising a rotary open-ended filteringdrum, mechanism for revolving said drum, a stationary casing in whichsaid drum is mounted, said drum having end rings, the outer surfaces ofwhich are grooved circiunferentially, air sealing rings mounted on saidcasing and having continuous inner edge portions of fibrous materialextending into said grooves to seal the joint between the ends of saiddrum and the casing, and clamping rings releasably securing said sealingrings to said casing and in their cooperative relationship to said endrings of the drum.

6. An air filtering apparatus comprising a rotary open-ended filteringdrum, a casing in which said drum is mounted, said casing beingconstructed to conduct the air to be filtered into contact with theperipheral surface of said drum but to confine said contactsubstantially to said surface, cam-driven pawl and ratchet mechanism forrevolving said drum, said mechanism including a cam follower and a camhaving a developed surface cooperating therewith to impart substantiallyuniform rotative motion to said drum approximately continuously.

7. An air filtering apparatus comprising a r0- tary open-ended filteringdrum, mechanism for revolving said drum, a casing having a filteringchamber in which said drum is mounted, the casing being constructed toconduct air to be filtered into contact with the peripheral filteringsurface of said drum but to confine said contact substantially to saidsurface, the casing also including end chambers into which the air flowsfrom the respective open ends of said drum, said casing including afourth chamber into which said end chambers conduct the air, a secondarybag-type filter unit comprising a header into which the air flows fromsaid fourth chamber, said header being provided with plurality ofoutlets, each outlet including a fixture constructed for the releasableattachment thereto of a filter bag, each of said bags having a ring towhich its open end is secured, means for releasably securing the ringsto said respective fixtures, and means operable from outside of saidheader for selectively closing said outlets for the removal andreplacement of the individual bags while the filtering operationcontinues uninterruptedly.

8. An air filteringapparatus'comprising'a ro tary open-ended filteringdrum, mechanism :for.

revolving said drum, a casinghaving a filtering chamber in which saiddrumis mounted, the casing being constructed to conduct air to befiltered into contact with the peripheral filtering surface of said drumbut to confine said contact substantially to said surface, the casingalso including end chambers into which the air flows from the respectiveopen ends of said drum, said casing including a fourth chamber intowhich said end chambers conduct the air, a secondary bag-type filterunit comprising a header having a plurality of outlets located side byside, means for conducting the air from said fourth chamber into saidhead, said header outlets being constructed for the releasableattachment thereto of individual filtering bags, and means in saidheader operable to control selectively the delivery of air to saidoutlets so that any bag can be removed and replaced without interruptingthe operation of the filtering system.

EUGENE C. GWALTNEY.

WILLIAM SHAW.

ELIOT B. MACLEAN.

10 REFERENCES CITED The following references are of record in the fileof this patent:

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